[ACS Applied Materials & Interfaces]Multifunctional Flexible Electromagnetic Interference Shielding Silver Nanowires/Cellulose Films with Excellent Thermal Management and Joule Heating Performances
作者：Chaobo Liang, Kunpeng Ruan, Yali Zhang and Junwei Gu*
關鍵字：Electromagnetic Interference Shielding, Silver Nanowires
論文來源：期刊
具體來源：ACS Applied Materials & Interfaces
發表時間：2020年
Flexible electromagnetic interference (EMI) shielding materials with excellent thermal conductivities and Joule heating performances are of urgent demand in the communication industry, artificial intelligence, and wearable electronics. In this work, highly conductive silver nanowires (AgNWs) were prepared using the polyol method. Cellulose sheets were then prepared by dissolving natural cotton in a green and efficient NaOH/urea aqueous solution. Finally, multifunctional flexible EMI shielding AgNWs/cellulose films were fabricated based on vacuum-assisted filtration and hot-pressing. AgNWs are evenly embedded in the inner cellulose matrix and overlap with each other to form a 3D network. AgNWs/cellulose films, with a thickness of 44.5 μm, obtain the superior EMI shielding effectiveness of 101 dB, which is the highest value ever reported for shielding materials with the same thickness. In addition, AgNWs/cellulose films present excellent tensile strength (60.7 MPa) and tensile modulus (3.35 GPa), ultrahigh electrical conductivity (σ, 5571 S/cm), and excellent in-plane thermal conductivity coefficient (λ∥, 10.55 W/mK), which can effectively dissipate the heat accumulation. Interestingly, AgNWs/cellulose films also show outstanding Joule heating performances, good stability, and sensitive temperature response at driving voltages, absolutely safe for the human body. Therefore, our fabricated multifunctional flexible AgNWs/cellulose films have broad prospects in the fields of EMI shielding and protection of outdoor large-scale power transformers and wearable electronics.
通訊工業、人工智能和可穿戴電子產品領域亟需具有優異導熱性能和焦耳熱性能的柔性電磁干擾（EMI）屏蔽材料。本文采用多元醇法制備高導電銀納米線（AgNWs），通過天然棉花溶解于綠色且高效的NaOH/尿素水溶液體系制備纖維素（cellulose）片，再經真空輔助抽濾與熱壓相結合的方法制備多功能AgNWs/纖維素屏蔽膜。研究結果表明，AgNWs均勻地嵌在纖維素基體中，且相互搭接成三維網絡結構。44.5 μm厚度的AgNWs/纖維素屏蔽膜具有101 dB的EMI SE，這是迄今報道過相同厚度下材料中的最高值。此外，AgNWs/纖維素屏蔽膜擁有卓越的拉伸強度（60.7 MPa）和拉伸模量（3.35 GPa），超高的導電率（s，5571 S/cm）和面內導熱系數（λ∥，10.55 W/mK），可以有效耗散聚酰亞胺電熱膜和陶瓷發熱片工作過程中產生的熱積聚。更有趣的是，AgNWs/纖維素屏蔽膜還顯示出了出色的焦耳熱性能，在對人體絕對安全的工作電壓下具有良好的穩定性和靈敏的熱響應性。因此，這種多功能柔性AgNWs/纖維素薄膜在戶外大型變電設備和人體可穿戴設備的EMI屏蔽防護領域的應用具有廣闊的前景。